Tomato chlorosis virus:  first report in Mayotte Island

In November 2005, a survey of symptomatic greenhouse tomato (Lycopersicon esculentum) plants was conducted on Mayotte Island, an island located in the northern part of the Mozambique Channel. Yellow leaf symptoms were observed on the lower and middle leaves of tomato plants from the northern (Koungou), western (Chiconi and Combani) and southern (Chirongui) regions. A flame-like pattern of the discoloured leaves and the similarity of the symptoms to the first description of Tomato chlorosis virus (ToCV, Crinivirus) on tomato in 2004 in Réunion Island (Delatte et al., 2006), suggested the possible involvement of the same virus in Mayotte Island.

Symptomatic leaf samples were collected from tomato plants from one greenhouse from each of the four affected regions. Total RNA was extracted from four samples using the Qiagen RNeasy Plant Mini Kit. For the detection of a potential crinivirus, a one-step RT-PCR was used with specific primers ToCV-172 and ToCV-610 primers (Louro et al., 2000). These primers amplify the highly conserved region of the heat shock protein 70 (HSP70) gene of ToCV. PCR products of the expected size (419 bp) were observed for all samples. Three PCR products were cloned using pGEM-T easy vector system II (Promega,) and sequenced (Genome Express) (EMBL Accessions AM748817, AM748818 and AM748819). Sequences obtained from the three amplicons had a 99% nucleotide identity (DNAMAN, Lynnon BioSoft). The highest nucleotide identities of the 412 bp fragment of the HSP70 gene were between 98 and 99% for ToCV isolates from France (EMBL Accessions DQ355214, DQ355215 and DQ355216), from Spain (EMBL Accessions AF233435, AF215818 and DQ136146), from Italy (EMBL Accessions AF234029 and AY048854) and from Réunion (EMBL Accession AM748816). To our knowledge, this is the first report of ToCV from Mayotte Island.